One of the exceptions was Harry's great-grandfather Henry Potter.
Harry Potter might be unique as the Boy Who Lived, the Chosen One, and the only known survivor of the Avada Kedavra curse....but it turns out, there's one surprising area where he's not unique at all.
Rowling has explained a lot about the whole family tree over on Pottermore, including where the family's wealth came from.
Since the publication of Harry Potter and the Deathly Hallows almost 10 years ago, the wizarding world has expanded far beyond what we read in the books.
Pottermore was launched in 2012, to allow fans to access snippets of writing from Rowling atop being sorted into a houses and brewing potions.
Henry served on the Wizengamot-a high wizarding court of law-and he publicly criticized the Minister of Magic after the Minister forbade wizards and witches from aiding Muggles during World War I. To many close to him, Henry went by Harry. Their last name comes from a 12th century wizard dubbed Linfred of Stinchcombe who was given the nickname Potterer.
And considering how much we love the famous one, it's cool to find out there was a second Harry Potter.
Adjudicators from Guinness stipulated that every child had to be wearing a Gryffindor tie and glasses, with a wand in their hands and Potter's trademark lightning scar on their foreheads.
If you don't know, the "Sacred Twenty-Eight" was a group of pure-blood wizarding families in the 1930s, while "Muggles" are non-magical folk.
James Potter later went on to marry Lily Evans, a muggle. "His outspokenness on the behalf of the Muggle community was also a strong contributing factor in the family's exclusion from the 'Sacred Twenty-Eight, '" ABC News noted.
Rowling has a habit of keeping interest and intrigue in the maigcal wizarding world alive by eking out new facts to keep fans engaged - a bit like that time she announced Dumbledore was gay.